Respect cardiologist Dr. Benjamin Levine said last year in an interview that exercise “needs to be part of your personal hygiene, like brushing your teeth or taking a shower.”
That’s because it prevents our muscular repair systems from weakening with age, a new study has shown.
Beginning in middle age, muscle strength and function gradually decline, increasing the risk of falls, fractures, and slower recovery after illness or injury.
The consequences extend beyond individual health. As populations age, muscle loss can increase demands on caregivers and healthcare systems. Preserving muscle function is therefore an important part of maintaining independence and quality of life. By preserving function, and therefore movement, independence is also preserved, and elderly individuals who are independent are more likely to pursue other activities known to support healthy aging like recreational sports.
One of the key regulators of muscle health is a growth pathway called mTORC1, which helps control protein production and muscle maintenance. In aging muscles, this pathway can become excessively active. When that happens, muscles focus more on building new proteins while becoming less efficient at removing damaged ones.
Over time, these damaged proteins accumulate inside muscle cells, placing them under stress and contributing to the gradual loss of strength associated with aging. Until now, scientists did not fully understand what causes this imbalance.
A team of researchers from Singapore General Hospital and Cardiff University identified a gene called DEAF1 as an important factor behind this process.
“Exercise tells muscles to ‘clean up and reset.’ Lowering DEAF1 helps older muscles regain strength and balance, almost like hitting the rewind button,” said Priscillia Choy Sze Mun, a research assistant in the Cancer and Stem Cell Biology Program at Duke-National University of Singapore (NUS) and the study’s first author.
“With millions of older adults at risk of muscle decline, understanding DEAF1 could lead to new ways to protect muscles and improve quality of life.”
The study’s co-authors working in the Duke-NUS laboratory – credit, Duke-NUS Medical School
According to the study, DEAF1 levels rise in aging muscles. As DEAF1 increases, it drives mTORC1 activity higher, disrupting the normal balance between protein production and protein removal. This imbalance accelerates muscle deterioration.
Under normal conditions, DEAF1 is regulated by a group of proteins known as FOXOs. However, FOXO activity naturally declines with age. As a result, DEAF1 is no longer kept under tight control, allowing its levels to increase and pushing muscles further away from repair and maintenance.
“Exercise can reverse this process, correcting the imbalance,” said Assistant Professor Tang Hong-Wen from the program at Duke-NUS.
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“Physical activity activates certain proteins which lower DEAF1 levels, bringing the growth pathway back into balance. This allows aging muscles to clear out damaged proteins, rebuild themselves properly, and help them stay stronger and more resilient.”
To test their findings, the researchers conducted experiments in both fruit flies and older mice.
The results were consistent across both species. Raising DEAF1 levels caused muscles to weaken more rapidly, while lowering DEAF1 restored healthier protein balance and improved muscle strength.
The researchers also found an important limitation. In some older muscles, DEAF1 levels become extremely high or FOXO activity drops significantly. In those cases, exercise alone may not be enough to fully restore the muscle’s repair capacity.
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This finding may help explain why some older adults experience greater benefits from exercise than others and highlights the importance of understanding the underlying biology of muscle aging.
The findings could also prove valuable for people recovering from surgery, illness, or chronic diseases such as cancer. Researchers suggest that targeting DEAF1 could potentially reproduce some of the beneficial effects of exercise at the molecular level, helping maintain muscle strength even when physical activity is limited.
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